It is known to terminate an underwater cable to a bulkhead of a subsea installation, to the back end of an underwater connector, or to a harness that provides an intermediate unit between a cable and another cable or subsea installation or connector. In certain known cable termination assemblies, a seal is formed at the rear of a cable termination chamber housing to seal against the cable jacket and thereby separate the interior of the housing from either ambient water to the rear thereof or from oil contained in a hose accommodating the cable. The seal is formed by a relatively hard plastic cone having an aperture through which the cable jacket extends and a radially inwardly facing surface for sealing against the jacket. The cone has a radially outwardly facing conical surface engaged by a radially inwardly facing conical surface of a seal energising member. The seal energising member is urged axially towards the cone member so as to compress it radially inwardly and form a seal with the cable jacket.
Another type of sealing arrangement known for use in cable termination assemblies provides a seal between axially adjacent chambers into which the cable extends. Each chamber contains a fluid such as oil or gel and is pressure balanced with respect to outside pressure by having a flexible wall the outside of which is exposed directly or indirectly to the outside environment. In order to separate the fluid in the two chambers a pair of back to back seals is provided. The cable passes through an aperture in a hard plastic seal holder and at each axially opposite side of the seal holder a first part of a respective elastomeric seal member engages round and seals against the cable jacket and a second part of the seal member engages round and seals against an axial extension of the seal holder.